It was an odd thing, to be driving along in rural Pennsylvania and spy a hosta growing by the side of the road in the middle of nowhere. I was reminded of this yesterday when I again drove past the spot - and found that the roadside had been scoured bald by machinery, for no apparent reason other than a mad burst of pseudosuburban tidiness.

But it was s urpise, back in the summer, rather like coming across those Mediterranean euphorbias growing by Heathrow Airport. But there they were, quite a few plants of Hosta ventricosa, flowering happily about half a mile from the soapwort I featured here back in early summer. And it turns out to be an unexpectedly interesting plant, and not just another hosta.

Hosta ventricosa grows wild in China and North Korea. It arrived in Britain in 1790, had reached France by 1800 and was grown by Josephine Bonaparte at Malmaison and painted there by Redouté in about 1802 (below left, click to enlarge) – although I’d say he’s done the ealy 19th century equivalent of a Photoshop job on it and made it look even better than it actually is. Anyway, it soon made its way to North America and became widely grown for its purple-striped flowers as well as for its broad, glossy ground covering foliage.

But here’s the thing. It’s the only natural tetraploid hosta there is, with twice the usual number of chromosomes, and this brings it extra robustness and thickness of foliage. It also produces seed without pollination and fertilization, and those seedlings are always exactly the same as the parent (a process called apomixis) – it’s as if the plants had simply been divided. So when it spreads by seed, the new plants are always the same as the parent.

And in North America, “spread” is exactly what it’s done – to sixteen north eastern states as far south as North Carolina, although the Pennsylvania Flora Project says it does not grow in our area of PA at all. Hmmm...

In Britain, the New Atlas of The British Flora – the usually infallible reference on plant distribution – says, surprisingly, that no hostas have ever been found in the wild anywhere in Britain. But with Hosta lancifolia also settling down in the north east US, along with H. plantaginea which has even taken up residence in Canada, I’m sure it won’t be long before we see hostas on British roadsides too.